The biggest prior threats to Burning Man's annual regeneration in the Black Rock Desert were U.S. land use laws, undercover cops and the media-perpetuated perception that the largest outdoor arts festival in North America is really just an excuse to get naked and do drugs.

But that was before the teeth-gnashing "ticket fiasco."

Two decades after the free spirits moved their party from San Francisco's Baker Beach to a dried up ancient lake bed 120 miles north of Reno, the annual pilgrimage with its drum circles, decorated art cars, guerilla theatrics and colorful theme camps has become too popular for its own good.

"The hard truth is that there are a lot of you who want to come to Black Rock City to celebrate your participation in the Burning Man culture this year, but not everyone will be able to attend," organizers said in an apologetic email — this after a lottery ticket sale intended to keep attendance below the federally permitted cap blew up in their faces.

Burning Man 2010 in Pictures and Words

The counter-culture celebration open to all under the principle of "radical inclusion" sold out for the first time last year with a crowd in excess of 53,000, forcing organizers to make plans to sell the bulk of the 2012 tickets through random drawings. But it wasn't until recently that many regulars got word they may not get in to this year's psychedelic adventure combining wilderness camping with avant-garde performance.

Whether opportunistic ticket scalpers are to blame or naive organizers were caught off guard is a topic raging among Burners in the blogosphere.

Many lament it will never be the same.

"The ticket fiasco means Burning Man has to make decisions now about who to let in and who to keep out," said Mark Van Proyen, chairman of the painting department at the San Francisco Art Institute who has attended the last 16 years in a row. "For that reason, it no longer can really truly be a radically inclusive event."

Van Proyen is among dozens of academics, scientists and other observers who marvel at the makeshift civilization as a living laboratory for research into anthropology, sociology, political science, and now, crisis management.

"People have always wondered what would happen if Burning Man kept growing, whether it would it be a victim of its own success," said Katherine Chen, an associate professor of sociology at the City College of New York who wrote the 2009 book, "Enabling Creative Chaos: The Organization Behind the Burning Man Event."

"It's been an issue all along, whether to grow the event and welcome all newcomers," said Chen, who first attended in 1998 and, wrote her dissertation about it at Harvard. "This is what societies have to confront every day."

Lee Gilmore, author of "Theater in a Crowded Fire: Ritual and Spirituality at Burning Man," said the "necessity to screen applicants" could cause divisions between "inner Burning Man elite" and the "newbies."

"There's been a long-standing tension about that — the super contributors," said Gilmore, who teaches American and religious studies at San Jose State. "There is the potential for a real cultural shift or a radical break from the event."

Organizers feel their pain. Many regulars have camped together for 10 years or more, Burning Man spokeswoman Marian Goodell said.

"Some kids have grown up in the camp and they feel like family to each other," she said. "We are trying to solve the problem of the community feeling ripped a part."

"At the same time, it was going to come to this at some point," she said.

The first 1,000-plus crowd in 1993 doubled each of the next three years. Attendance climbed to 23,000 in 1999. It was capped at 50,000 under the most recent five-year permit granted by the Bureau of Land Management, which expired in 2010.

Since then, the event has operated under temporary annual permits. Goodell said they interpret the current permit to allow "in the neighborhood" of 58,000 people to be present at any one time in the 5-square-mile encampment.

The lottery system — releasing tickets in various stages at various prices up to $420 — was intended to be the fairest way to give everyone a chance to attend. The thinking was long-time attendees would grab the bulk of the earliest batch of 10,000.

But critics say organizers failed to anticipate so many real-world scalpers would snatch up tickets for resale at huge profits. The Aug. 27 to Sept. 3 festival culminates with the burning of a towering wooden effigy

"This was a complete failure," said Cory Mervis, a member of a regional Burning Man group in Las Vegas and local arts producer.

However, Goodell said organizers believe the ticket shortage has less to do with scalpers than the extraordinary level of interest.

Others are not sympathetic to those without tickets.

"I sat in line at Space Mountain for two hours once and somebody threw up and they closed it," said Rick Dinoso, a past attendee from Reno who calls the complainers "crybabies."

Officials acknowledged in a Feb. 15 email that the lottery had left "an inordinately large" core of longtime contributors ticketless, punching "significant holes" in the artistic, civic and functional infrastructure and "putting the integrity of the event itself at risk."

So, at the risk of making the matter worse, organizers announced they were abandoning plans for a future lottery. They would instead allocate tickets to leaders of selected theme camps, performance groups and others to distribute as they see fit. A selection committee will use a published set of guiding principles for the distribution.

That's still an exclusion that amounts to "squatter's rights," Van Proyen said.

Gilmore gives organizers high marks for their emergency response. But she said they're walking a fine line trying to regulate who is on the bus and off the bus at a place where pot-smoking guitar players and trippy looking women wearing nothing but sunglasses rub shoulders with Wall Street bankers and Silicon Valley software execs.

"Burners don't like bureaucracy," she said. The more an event has "to interface with the restrictions and reality of the default world," she said, the more organizers have to think about sustaining the event in a way true to their principals.

Goodell said they've had to change the rules before.

For example, tiki torches were banned one year after a bale of hay caught fire.

More important than the event itself, said Goodell, is keeping Burning Man's spirit alive.